1. Field of the Invention
The present invention relates to moving image processing for converting a frame rate, and more particularly to conversion into a higher frame rate such as conversion of an image of 60 hertz (Hz) into an image of 120 Hz.
2. Description of the Related Art
Conventionally, as a technique for suppressing motion blurs or flickers generated when a video is displayed by a display apparatus, there has been known a video display method for generating sub-frames different from each other in frequency component from image data, and alternately displaying the sub-frames at a multiplied speed (as discussed in Japanese Patent Application Laid-Open No. 2006-184896).
The video display method generates, from input image data, high-frequency emphasized image data where a high-frequency component is emphasized, and low-frequency image data including a low-frequency component where a high-frequency component is suppressed, and alternately displays these image data pieces at the multiplied speed. This technique can suppress flickers and reduce motion blurs.
Moreover, there is known a video display method for executing pre-processing for minimum value filter processing on input image data, and then, generating high-frequency emphasized image data where a high-frequency component is emphasized and low-frequency image data including a low-frequency component where a high-frequency component is suppressed. It is known that the method can improve a blur of a contour of a character and the like (as discussed in Japanese Patent Application Laid-Open No. 2009-271135.)
However, in the video display method for performing the minimum value filter processing on the input image data, for example, if a black-dot isolated noise exists within a filter application size, the noise is selected as the minimum value and the noise is extended.